Scavenging ejector



Oct. 19, 1926. 1,603,957

A. T. KASLEY SCAVENGING EJECTOR' Filed Dec. 31 1920 7'0 EXHAUST MAN! FOLD Patented Get. 19, 1926.

UNH'ED STATES PATENT OFFICE.

ALEXANDER T. KASLEY, OF ESSINGTON, PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VANIA.

SGAVENGING EJECTOR.

Application filed. December 31, 1920.

My invention relates to scavenging apparatus for internal combustion engines in which a flow of air at atmospheric pressure is drawn by suction through the engine cylinders to remove the burned gases and to fill the cylinders with a charge of pure air, and has for its object to provide an apparatus of the character designated which shall be simple and compact in structure, readily attachable to the exhaust manifold of en gines of standard construction and which shall, by utilizing the force of the exhaust discharge to scavenge and to refill the cylinders, attain a high degree of economy in operation.

These and other objects which will be made apparent throughout the further description of my invention are attained by means of apparatus embodying the features herein described and illustrated in the draw ings accompanying and forming a part hereof.

In the drawings, Fig. 1 is a diagrammatic sectional view of a scavenging apparatus embodying my invention.

Fig. 2 is a view along the line 11-11 of Figure 1.

Figure 3 is a detail view of a valve structure suitable for use in connection with applicants scavenging mechanism.

Figure 4 is a graphical illustration of the pressure variations within the exhaust manifold and periods of the valve operation.

Figure 5 is a view similar to Fig. 2 illustrating a modification of my device.

Fig. 6 is a diagrammatic view showing the application of my invention to an internal combustion engine.

It is well known that the efficiency of an internal combustion engine and particularly of an engine of the Diesel type is considerably increased by a thorough scavenging of the cylinders of burned gases at the completion of the working stroke. It has heretofore been proposed to utilize the kinetic energy of the burned gases which are discharged at a considerable pressure during the early opening of the outlet ports to withdraw the remaining gases and to draw in air for scavenging and refilling the cylinders with pure air for a succeeding charge. Such an arrangement is disclosed in an application. Serial No. 329,807, filed October 10, 1919, by myself and assigned to the West- Serial No. 434,365.

Electric and Manufacturing Com providing positively operable means for connecting the vacuum chamber with the eX haust manifold during periods of low pressure therein.

As illustrated in Fig. 1, exhaust gases of an internal combustion engine are conducted through an exhaust manifold 10 to a nozzle chamber 11. which is provided with a plurality of nozzles 12 arranged to discharge the exhausted gases into an ejector 18. connected directly with the nozzle chamber 11 so that the gases discharged into it are subjected to little or no frictional losses andare expanded by collectively grouped nozzles in such a way as to be most effectively discharged through the ejector passages. The ejector may be of any suitable conformation, but is preferably constructed with a converging portion 14 and a divergins;- diffuser portion 15. A separate source of motive fluid is supplied to the ejector 13 through nozzles 16 extending through the chamber 11. The nozzles 16 are preferably so arranged as to discharge jets concentrically and interiorly of the nozzles 12 as indicated at 17, and communicate with a nozzle chamber 18 which is supplied with motive fluid through a conduit 19 from any convenient source. An energy-storing reservoir 20 is arranged with respect to the ejector 13 so as to be evacuated by the discharge of fluid through the nozzles 12 and 16. As shown, the chamber 20 surrounds the ejector 13 and may, if desired, be made integral therewith. An annular row of openings 21 affords communication between the chamber 20 and the ejector 13, and are preferably located adjacent the nozzles 12 and 16. One or more valves 22 are arranged The exhaust manifold 10 is shown as i to provide communication between the exhaust chamber 11 and the reservoir 20. The valves 22 are provided with a suitable operating mechanism. as lever mechanism 22, operatively connected to the engine. and arranged to open the valve 22-at periods of low pressure within the exhaust manifold.

For example, I show in Fig. 6 an internal combustion engine 30 having my impr ved apparatus applied thereto. A, 31 is shown the engine shaft which carries a cam member 32. Bearing on the cam member 32 is an actuating rod 33 which is operatively connected to the lever mechanism 22 so that the valve 22 is opened and closed in timed relation to the rotation of the shaft The graph in Figure 4: illustrates the pressure variations in the exhaust manifold and the periods during which the valve 22 should be opened and closed. The ordinates represent the pressure in pounds ab solute within the exhaust manifold. The aeriods during which the valve 22 should e closed are designated at a and the periods during which the valve 22 should be opened at Z).

A plurality of small ports 23 may be provided in the upper wall of the nozzle chamber 11. These ports should be adjacent the opening 21 and substantially within that pa-rt of the upper wall of the chamber 11 defined by the extension of the con- Verging walls 14. It is to be understood that under certain operating conditions it may be desirable to omit the ports 23, as is shown in Fig. 5.

The operation of my improved scavenging device is as followsz-Before starting up the engine, steam or other fluid under pressure may be delivered to the nozzles 16 for the purpose of evacuating or partially evacuating the reservoir 20 and the exhaust passages 10 and 1.1. Upon starting the engine. the successive charges of exhaust gases delivered to the nozzles 12 cooperate with the steam jets 17 reducing the pressure within the reservoir 20 and in ejecting the exhaust products from the system. If desired, the steam jets may be so proportioned as to act merely as a seal for maintaining the vacuum within the reservoir 20 produced by the discharging products of combustion. When an outlet port of the engine cylinder is first uncovered, highly compressed gases are released from the cylinder and delivered to the nozzle chamber 11. The passage of these gases through the ejector 13 produces a high vacuum in the back flow from the ejector 13 to the chamber 11 and to the reserv0ir20 being prevented 'ments.

by the steam jet discharging into the ejector. P ior to the release of a successive charge of burned gases through the manitold 10, the valve 22 is closed. The reservoir 20 should be of such a size as to withdraw not only all of the burned from the cylinder but also some of the scavenging air. It is particularly desirable to over-scavenge the cylinders of a multi-cylindcr me of the Diesel type so that scav g air fills the exhaust passages to the manifold, since air in the exhaust passages may be forced back into the engine cylinder by the momentary rise of pressure caused by the release of burned gases in another cylinder. This increases the mean effective pressure in the cylinder and at the same time insures the cylinder being filled with pure air.

ll hen the mechanism is provided with the ports 23., the portion of theexhaust gases delivered to the chamber 11 under high pressure which passes through the ports 23 is drawn into tne ejector, due to the entraining action of the high pressure gases and discharged through the diffuser 15. When the pressure of the exhaust gases falls, the low pressure gases in the chamber 11 pass through ports 23 and the opening 21 into the vacuum reservoir 20, the back flow of gases from the ejector to the chamber 11 and to the reservoir 20 being prevented by the action of the steam jets 17. The chambers 11, manifold 10 and consequently engine cylinders are thus evacuated and a flow of scavenging air induced therethrough.

It is evident that-an internal combustion engine equipped with my improved scavenging mechanism herein as described and illustrated, may be scavenged more efficiently and more economically than engines provided with the usual scavenging arrange- The amount of steam or other 1notive fluid necessary for maintaining the proper vacuum is not excessive since it may be reduced to the minimum at which the seal between the ejector and the reservoir vill be maintained. 7 i

lVhile I have shown my invention in but one form, it will be obvious tothose skilled in the art that it is not so limited, but is susceptible of various other changes and nodilications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

W hat I claim is:

1. The combination with an internal combustion engine having an exhaust manifold, of a reservoir, an ejector mechanism actuby the exhaust gases for evacuating the reservoir, continuously acting suplemental ejecting means for maintaining a sub-atmospheric pressure in the reservoir and preventing a back flow of gases into the reservoir during periods of non-flow of exhaust gases, valve means affording comunication between the exhaust manifold and the reservoir, and means for opening and closing said valve means in timed relation to the opera tion of the engine.

2. The combination With an internal combustion engine having an exhaust manifold, of a reservoir, an ejector mechanism actuated by the exhaust gases for evacuating the reservoir, continuously acting supplemental ejecting means for maintaining a sub-atmospheric pressure in the reservoir and preventing a back flow of gases into the reservoir during periods of non-flow of exhaust gases, valve means affording communication between the exhaust manifold and the reservoir, and means for operating said valve means in timed relation to the operation of the engine to open said communicating means during periods of relatively low pressure in the exhaust manifold.

3. The combination with an internal combustion engine having an exhaust manifold, of a reservoir, continuously acting evacuating means for maintaining a sub-atmospheric pressure in the reservoir, ejecting means operated by the exhaust gases under pressure for creating a further reduction in pressure in the reservoir during periods of high exhaust pressure in the manifold, valve means affording communication between the reservoir and the exhaust manifold, and means operable in timed relation to the operation of the engine for opening and closing the valve means.

4:. The combination with an internal combustion engine having an exhaust manifold, of a reservoir, continuously acting evacuating means for maintaining a sub-atmospheric pressure in the reservoir, ejecting means operated by the exhaust gases under pressure for creating a further reduction in pressure in the reservoir during periods of high exhaust pressure in the manifold, valve means affording communication between the res rvoir and the exhaust manifold, and means operable from the engine for effecting an opening of said valve means during periods of relatively low pressure in the exhaust manifold and a closing of said valve means as the pressure in the exhaust manifold increases.

In testimony whereof, I have hereunto subscribed my name this 28th day of December, 1920.

ALEXANDER .T. KASLEY. 

